Air-blast and ground shockwave parameters, shallow underground blasting, on the ground and buried shallow underground blast-resistant shelters: A review

2021 ◽  
pp. 204141962110489
Author(s):  
S M Anas ◽  
Mehtab Alam ◽  
Mohammad Umair
Keyword(s):  
High Performance ◽  
Prediction Models ◽  
High Performance Concrete ◽  
Progressive Collapse ◽  
Mach Reflection ◽  
Clear Understanding ◽  
Underground Blasting ◽  
Air Blast ◽  
Extreme Loads ◽  
Underground Blast

Weak political systems and poor governance in certain developing countries are found to have a war-like environment where structures are being targeted by blasts and bombs. Industrial blasts due to frail know-how and mishandlings are also quite common. Recent accidental explosions like that occurred at the Beirut Port, Lebanon (August 2020); ammunition depot in the outskirt of the Ryazan City of Russia (November 2020) are of concern for the safety of adjacent building infrastructure and their users. Such intense loading events cause damage to certain elements of a structure which may result in disproportionate or progressive collapse. It necessitates a clear understanding of the phenomenon of the blast and extreme loads induced out of it, and response of the target structure under such loadings. In this study, the state of research on air-blast and ground shockwave parameters, shallow underground blasting, and on the ground and buried shallow blast-resistant shelters are presented. The phenomenon of the self-Mach-reflection of the explosion, loading parameters and empirical blast models available in the open literature followed by the damage criteria for the buildings subjected to the underground blasting and available peak particle velocity (PPV) prediction models have been discussed. To make the application of advanced materials such as fibrous concrete, ultra-high performance concrete, FRP composites, etc., it is important to comprehend the existing blast/shock-resistant shelters and their response under such loading. The shelters are primarily designed by incorporating features of the materials like high degree of deformability/ductility, use of the shock-isolation panels and the mechanism for controlling crack formations. Finally, conclusions and recommendations for future studies are summarised. This paper presents prospects to engineers, town planners, researchers, policymakers and members of the core drafting sectional committees to understand the phenomenon of the blast and extreme loads induced out of it.

scholarly journals Use of Fiber Brag Gating Sensors in civil engineering applications

2021 ◽  
Author(s):  
Zahra Yazdizadeh
Keyword(s):  
High Performance ◽  
Civil Engineering ◽  
Prediction Models ◽  
High Performance Concrete ◽  
Shrinkage Strain ◽  
Second Phase ◽  
Engineering Applications ◽  
Fbg Sensors ◽  
Important Time ◽  
Creep And Shrinkage

This research presents an overview of development and application of Fiber Bragg Grating sensors (FBG) technology in civil engineering applications. The primary focus of this research is the use of FBGs to investigate two most important time-dependent properties of concrete namely: creep strain and shrinkage strain. The first phase of this investigation is focused on using FBG sensors to measure the concrete strains in unreinforced concrete beams and cylinders to determine modulus of elasticity, the modulus of rapture and fracture energy of concrete. The second phase of this research is designed to investigate the creep and shrinkage using FBG sensors. Normal strength concrete (NC), High performance concrete (HPC) and ultra-high performance (UHPC) specimens’ are used to measure creep and shrinkage strains and to compare the values with typical prediction models. The measured creep and shrinkage strains are compared to four different models to determine which model is the most accurate.

scholarly journals Durability of High Performance Concrete (HPC) Subject to Fire Temperature Impact

2016 ◽  
Vol 62 (4) ◽  
pp. 73-94 ◽  
Author(s):  
W. Jackiewicz-Rek ◽  
T. Drzymała ◽  
A. Kuś ◽  
M. Tomaszewski
Keyword(s):  
High Temperature ◽  
High Performance ◽  
High Performance Concrete ◽  
Water Impact ◽  
Fire Temperature ◽  
Extreme Loads ◽  
Concrete Properties ◽  
Concrete Mix ◽  
Temperature Impact ◽  
Aeration Process

AbstractIn the recent years a tendency for design of increasingly slender structures with the use of high performance concrete has been observed. Moreover, the use of high performance concrete in tunnel structures, subject to high loads with possibility of extreme loads occurrence such as fire, has an increasing significance.Presented studies aimed at improving high performance concrete properties in high temperature conditions (close to fire conditions) by aeration process, and determining high temperature impact on the concretes features related to their durability.In this paper it has been proven that it is possible to obtain high performance concretes resistant to high temperatures, and additionally that modification of the concrete mix with aerating additive does not result in deterioration of concrete properties when subject to water impact in various form.

Analysis on Creep Property and Model of Bridge Girder Concrete with Various Mix Proportions

2013 ◽  
Vol 368-370 ◽  
pp. 1487-1494
Author(s):  
Fei Guo ◽  
Hong Gen Qin ◽  
Peng Fei Cao ◽  
Guan Guo Liu ◽  
Yun Sheng Zhang
Keyword(s):  
High Performance ◽  
Material Parameter ◽  
Prediction Models ◽  
High Performance Concrete ◽  
Creep Property ◽  
Scientific Basis ◽  
Concrete Creep ◽  
Shrinkage And Creep ◽  
Bridge Girder

Combined with the construction of Jinghang Canal Bridge of Jiangliu highway, shrinkage and creep property of the cast-in-situ high performance concrete of bridge girder was researched. The results showed early shrinkage and creep development of the high performance concrete was relatively rapid, and creep tended to be stable 120 days later. With the admixture increasing, shrinkage and creep of the concrete were reduced. Meanwhile, early creep rate deceased. Similar results applied to the reduction of sand rate and water-cement ratio. Based on creep prediction models both at home and abroad, hyperbolic power function and exponential function model were put forward, taking the influence of material parameter and environmental factors on shrinkage and creep into consideration. In accordance with the model, concrete creep formula was given out and would provide a relatively scientific basis for practical prediction of concrete creep.

scholarly journals Investigation of the Impact of Graphene Nanoplatelets (GnP) on the Bond Stress of High-Performance Concrete Using Pullout Testing

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7054
Author(s):  
Fouad Ismail Ismail ◽  
Yassir M. Abbas ◽  
Nasir Shafiq ◽  
Galal Fares ◽  
Montasir Osman ◽  
...  
Keyword(s):  
Bond Strength ◽  
High Performance ◽  
Prediction Models ◽  
High Performance Concrete ◽  
Control Sample ◽  
Design Procedure ◽  
Graphene Nanoplatelets ◽  
Steel Reinforcement ◽  
Bond Stress ◽  
The Impact

Efficient load transmission between concrete and steel reinforcement by bonding action is a key factor in the process of the design procedure of bar-reinforced concrete structures. To enhance the bond strength of steel/concrete composites, the impact of graphene nanoplatelets (GnP) on the bond stress and bond stress–slip response of deformed reinforcement bars, embedded in high-performance concrete (HPC), was investigated using bar pullout tests. In the current study, 36 samples were produced and examined. The main variables were the percentages of GnP, the steel reinforcement bar diameter, and embedded length. Bond behavior, failure mode, and bond stress-slip response were studied. Based on the experimental findings, the inclusion of GnP had a significant favorable influence on the bar-matrix interactions due to the bridging action of GnP as a nano reinforcement. For 0.02 wt.% of GnP, the bond strength was enhanced by more than 41.28% and 53.90% for steel bar diameters of 10 and 16 mm, respectively. The HPC-GnP mixture displayed a reduction in the initial slippage in comparison to the control sample. The test findings were compared to the prediction models created by other researchers and the ACI 408R-12 code.

scholarly journals Optimization of Arabian-Shield-Based Natural Pozzolan and Silica Fume for High-Performance Concrete Using Statistical Design of Experiments

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yassir M. Abbas ◽  
M. Iqbal Khan
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
Prediction Models ◽  
High Performance Concrete ◽  
Blended Cement ◽  
Statistical Design ◽  
Partial Replacement ◽  
Statistical Design Of Experiments ◽  
Natural Pozzolan ◽  
Surface Design

In this study, the optimum dosages of silica fume (SF) and natural pozzolan (NP) were experimentally and statistically assessed for the best strength and durability properties of high-performance concrete (HPC). SF and NP were used as partial replacement Portland cement (PC) by up to 12 and 25 wt.%, respectively. Additionally, the prediction models based on second-level factorial (SLF) and response surface design (RSD) were formulated to estimate the HPC properties and their validation. The SLF-based model was further employed to investigate the significance and interactions of the PC, SF, and NP blends. The 28-day strength of the blended-cement HPC with a water-to-binder ratio w / b of 0.25 was generally higher than that of the control concrete. The positive synergy of PC–NP–SF was also observed in the HPC permeability. The paired t -test of the mean square error (MSE) of the SLF- and RSD-based models revealed that the MSE of the former was notably less than that of the latter. These results established the superiority of the SLF-based model over the RSD-based model. Therefore, the SLF-based model was further employed to investigate the importance of various binders.

Prediction Model and Relationship of Compressive and Tensile Strengths for High Performance Concrete

2013 ◽  
Vol 377 ◽  
pp. 92-98
Author(s):  
Mohammad Iqbal Khan
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Silica Fume ◽  
High Performance ◽  
Ordinary Portland Cement ◽  
Prediction Models ◽  
High Performance Concrete ◽  
Analytical Prediction ◽  
Fuel Ash

Analytical models for compressive strength and tensile strength of high performance concrete are presented. High performance concrete was developed using binary and ternary blending combinations consisting of ordinary Portland cement, pulverised fuel ash and silica fume. Pulverised fuel ash and silica fume were incorporated as partial cement replacements for the preparation of various combinations of blended systems. Compressive strength and tensile strength of concrete containing ordinary Portland cement, pulverised fuel ash and silica fume at various ages are reported. Based on the experimentally obtained results, analytical prediction models were developed. These models enabled the establishment of isoresponse contours showing the interactive influence between the various parameters investigated.

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